Hitchhiking ghosts could be seducing travellers on a busy road near Swansea, a paranormal investigator has claimed.

Gavin Davies, the author of Ghost Sex, says he is investigating a spate of incidents where unsuspecting drivers are seduced by hitchhiking ghouls.

One of them involved a Pembrokeshire man who told Mr Davies he was seduced by a figure disguised as a beautiful woman hitchhiking on the A40.

“I was approached by a man who did not want to be identified because it could expose him to ridicule, who told me he picked up a hitchhiker who turned out to be a ghost that seduced him,” Mr Davies said.

“Now, I’m aware that stuff like this is often intended as erotica and people have fantasies about it. And at first I thought it was a wind up call. But this man genuinely believed he was seduced by a paranormal entity.

“He said that he was driving back from a date that hadn’t gone as planned.

“He saw a beautiful woman on the side of the road and he picked her up.”

Mr Davies said the man, known as “John,” then pulled over and took the mysterious woman into a public toilet.

He said the ghost then seduced John in terms too graphic to describe.

‘John’ wrote: “Then I started to smell something strange, at first I thought it was like a cigarette smell.

“I was choking, and I thought I was going to die. I was crying and everything. I was passing out.

“I just wanted a policeman to start banging on the window and save me.

“I pushed her back with all my force and there was not a pretty girl on me but some haggard, disgusting old woman with some kind of awful skin condition.

“I just screamed and screamed and she just vanished.”

Mr Davies said he believes the man could have been affected by sleep paralysis after nodding off.

Sleep paralysis is a condition where the victim feels wide awake but is unable to move a muscle.

It is often accompanied by delusions of being watched by a menacing presence.

“In the renaissance era they believed that the paralysis was caused by succubi, who would seduce people while they were asleep,” Mr Davies said.

His book “Ghost Sex” has already sold 3,000 copies online and topped supernatural charts on the Amazon Kindle store.

He is also the editor of Paranormal Chronicles, a website that looks into suspected sightings of ghosts and UFOs.

“Writing this book has taken its toll on me,” Mr Davies said.

“This is just one account, and many of the others are far more graphic and quite traumatic to research.